1. Field of Invention
This disclosure generally relates to in situ, ex situ and inline methods of process monitoring, optimization and device fabrication methods in semiconductor processes.
2. Related Art
A number of methods exist for monitoring semiconductor processes in situ, ex situ and inline, where low pressure, high temperature, reactive gases, plasma discharge, or other extreme conditions are required for fabrication. One objective may be to optimize the process conditions to produce the highest quality results in the shortest time, with least expenditure of energy or material, i.e., production efficiency. Another objective may be to detect endpoint conditions in a fabrication step, i.e., accuracy and uniformity. For example, secondary ion mass spectrometry (SIMS) may be used for endpoint detection in sputter etching processes. Residual gas analysis (RGA) may be used to control partial pressure in reactive deposition and etch systems. Quartz crystal oscillators may be used to monitor and control deposition thickness. However, all these monitoring, endpoint detection and optimization, and control systems typically require complex equipment and/or vacuum conditions. Therefore, there is a need for simplified means of performing many types of process monitoring and control.